People posting jokes or embarrassing details about friends on social networking sites such as Facebook could could be sued for libel, a lawyer has warned.

The caution comes after a businessman who was the target of a fake profile Facebook was awarded £22,000 in damages at the High Court.

According to Hanna Basha a partner at Carter Ruck solicitors the case, which is the first of its kind in the UK, is “likely to set a trend for more people to bring such actions.”

Mathew Firsht won the case - which is part of what the law calls “defamation”: the act of denting someone’s reputation - against an old school friend, Grant Raphael.

Mr Raphael created a profile in Mr Firsht's name on the social networking site.

The judge heard that the profile, which was on Facebook for 16 days until it was taken down, concerned Mr Firsht's whereabouts, activities, birthday and relationship status. It also falsely indicated Mr Firsht’s sexual orientation and political views.

Mr Raphael also created a group called " Has Mathew Firsht lied to you?", which alleged that Mr Frisht owed substantial sums of money which he had repeatedly avoided paying by lying.

In his defence Mr Raphael said that "strangers" who attended a party at his house sneaked off to a spare bedroom and created the profiles on his PC. However, the judge rejected this describing it as a “lie”.

Ms Basha said that this was “a clear sign that no matter how much fun Facebook is, people should still be careful in what they publish about others”

“Previously the informality of social networks tended to make people think that they were not governed by the same laws as more mainstream media, such as the television and newspapers.

“If someone publishes information on Facebook which invades another person's privacy or defames that person then the publisher of the information can be sued,” she added.

Mr Raphael was ordered to pay £15,000 for libel and £2,000 for breach of privacy to Mr Frisht’s company, and £5,000 for personal libel.

Find out more about how libel laws affect home PC users.